Age- and Gender-Specific Familial Risks for Venous Thromboembolism

Abstract

Background-This nationwide study sought to determine age-and gender-specific familial risks in siblings hospitalized for venous thromboembolism (VTE). Methods and Results-The Swedish Multigeneration Register on 0-to 75-year-old subjects was linked to the Hospital Discharge Register for the years 1987-2007. Standardized incidence ratios were calculated for individuals whose siblings were hospitalized for VTE compared with those whose siblings were not affected. Among a total of 45 362 hospitalized cases with VTE, 2393 affected siblings were identified, with a familial standardized incidence ratio of 2.45 (95% confidence interval [CI], 1.66 to 3.61). Gender-specific differences in incidence rates were observed. The familial risks were significantly increased from the age of 10 to 69 years, with a familial standardized incidence ratio of 4.77 (95% CI, 1.96 to 10.83) at ages 10 to 19 years, which decreased to 2.08 (95% CI, 1.35 to 3.20) at ages 60 to 69 years, although the absolute risk increased with age. The familial standardized incidence ratios for siblings with 2 and Ն3 affected probands were 51.87 (95% CI, 31.47 to 85.00) and 53.69 (95% CI, 25.59 to 108.50), respectively. Spouses had low familial risks (standardized incidence ratioϭ1.07; 95% CI, 1.04 to 1.10; observed spouse casesϭ3900). Conclusions-Familial factors, although influenced by age and gender, are important risk factors for VTE. The present study shows that VTE is aggregated in families and suggests that uncovering the sources of familial aggregation (genetic and nongenetic) may be worthwhile. Moreover, in a small fraction of siblings, the familial risk was very high, suggesting segregation of rare but strong genetic risk factors.

Risk of deep vein thrombosis and pulmonary embolism in asthma

“…Observed incidence rates of VTE in the Norwegian population were similar to rates for first events in other western European countries, including France and Sweden [25,26]. Therefore, we believe that the Norwegian population could be used as an adequate reference population in our study.…”

Importance of Family History as a Risk Factor for Venous Thromboembolism

“…In the current edition of Circulation, Zöller and colleagues 4 present the results of their database linkage study that explored the role of family history as a risk factor for VTE. Using unique individual national identifiers to link data from the national Swedish Multigenerational Registry (a family data set that links second-generation Swedes born since 1932 with their siblings) with information from the Swedish Hospital Discharge Register (which contains complete data on all hospital discharge diagnoses since 1986), they identified 45 362 patients hospitalized for deep vein thrombosis, pulmonary embolism, thrombophlebitis (including superficial phlebitis), or thrombosis in unusual sites over a 21-year period.…”

Familial Transmission of Venous Thromboembolism

“…This is in-line with previously published nationwide family studies. 17,18,[40][41][42][43][44] A further observation is that the biological familial risk (SIR=1.51) was slightly lower than previously published (familial risk ≈2).…”

“…12, [14][15][16][17][18][19][40][41][42][43][44] The explanation may, however, simply be because of the relatively lower power in a study only including adoptees. However, a possible hypothesis for the modest familial risk of 1.51 is that the higher familial transmission observed in nonadopted offspring 17,18,[40][41][42][43][44] is because of the sum of interactions between familial genetic and environmental factors.…”